Test and measurement device with a pistol-grip handle

ABSTRACT

A clamp meter configured to receive a removable and rechargeable battery pack. The clamp meter includes a main body having a first axis, a handle, a clamp, a trigger, and a display. The handle has a second axis and includes a first recess configured to receive the battery pack. The first recess includes at least first and second electrical terminals which are exposed when the battery pack is not inserted into the first recess. The second axis forms an oblique angle with the first axis, and the battery pack is inserted into the first recess along the second axis. The clamp is coupled to the main body, aligned with the first axis, and operable to measure an electrical characteristic of a conductor based on an induced current. The trigger is operable to selectively open and close the clamp, and the display configured to display an indication of the electrical characteristic.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/626,667, filed Sep. 25, 2012, which is a continuation of U.S. patentapplication Ser. No. 12/936,808, now U.S. Pat. No. 8,274,273, whichentered the U.S. under 35 U.S.C. §371 on Apr. 1, 2011 as anational-stage entry of PCT Application No. PCT/US2009/040101, filedApr. 9, 2009, which is a continuation-in-part of U.S. patent applicationSer. No. 12/399,835, filed Mar. 6, 2009, now U.S. Pat. No. 8,251,157,the entire contents of all of which are hereby incorporated byreference. U.S. patent application Ser. No. 12/936,808 also claims thebenefit of U.S. Provisional Patent Application No. 61/043,455, filed onApr. 9, 2008, and U.S. Provisional Patent Application No. 61/095,053,filed on Sep. 8, 2008, the entire contents of both of which are herebyincorporated by reference.

BACKGROUND

Test and measurement devices, such as digital multi-meters (“DMM's”),clamp meters, thermometers, stud sensors, and the like, are powered byreplaceable or rechargeable alkaline batteries. For example, a typicaltest and measurement device includes a receiving area on a bottom orback face of the device that is adapted to receive a plurality (e.g., 2,3, 4, etc.) of alkaline batteries. The batteries are secured in thereceiving area via a removable door or plate which is fixedly attachedto the device's housing. The alkaline batteries, which typically have anominal voltage of 1.5V, are connected in series to provide operationalpower to the devices.

In many instances, these devices have dedicated functionalities. Forexample, a DMM is capable of measuring electrical characteristics suchas voltage and current and displaying an indication of the measuredelectrical characteristic. Clamp meters have similar or identicalfunctionality to the DMM, but differ in the manner in which some of theelectrical characteristics are measured (e.g., using inductivecoupling). Thermometers, such as infrared (“IR”) thermometers, include adetector and a laser source for projecting an indication of the locationor size of a sensed area. Stud sensors include the capability ofdetecting wooden or metal studs hidden behind a surface and providing anindication of a sensed stud via light emitting diodes (“LEDs”) or anaudible indicator such as a small speaker.

SUMMARY

In one embodiment, the invention provides a test and measurement deviceconfigured to receive a removable and rechargeable battery pack. Thetest and measurement device includes a main body having a first axis, ahandle having a second axis, a first recess, and a second recess. Thefirst recess includes a mating interface for receiving, along the secondaxis, a first attachment operable to provide power to the test andmeasurement device, and the second recess is configured to receive asecond attachment operable to provide operational control for the testand measurement device. The handle is offset from the main body of thetest and measurement device, and is attached to a lower portion of themain body along the second axis such that the handle forms an obliqueangle with respect to the first axis.

In another embodiment, the invention provides a clamp meter configuredto receive a removable and rechargeable battery pack. The clamp meterincludes a main body having a first axis, a handle, a clamp, a trigger,and a display. The handle has a second axis and includes a first recessconfigured to receive the battery pack. The first recess includes atleast first and second electrical terminals which are exposed when thebattery pack is not inserted into the first recess. The second axisforms an oblique angle with the first axis, and the battery pack isinserted into the first recess along the second axis. The clamp iscoupled to the main body, aligned with the first axis, and operable tomeasure an electrical characteristic of a conductor based on an inducedcurrent. The trigger is operable to selectively open and close theclamp, and the display is configured to display an indication of theelectrical characteristic.

In another embodiment, the invention provides a method of operating aclamp meter that includes a main body, a handle, a clamp, and a pair ofelectrical leads. The method includes powering the clamp meter with aremovable battery pack inserted into a recess of the handle; sensing,using the clamp, a first electrical characteristic based on an inducedcurrent; measuring, based on signals received through the pair ofelectrical leads, a second electrical characteristic; and displaying, ona display, an indication of the first electrical characteristic and thesecond electrical characteristic. The pair of electrical leads areoperable to receive a pair of electrical probes, the battery pack isinserted along a first axis, the clamp is aligned along a second axis,and the first axis and the second axis form an oblique angle.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a handle of a test and measurementdevice according to an embodiment of the invention.

FIG. 2 is a front view of the handle of FIG. 1.

FIG. 3 is a bottom view of the handle of FIG. 1.

FIG. 4 is a perspective view of a battery pack.

FIG. 5 is an exploded view of the battery pack of FIG. 4.

FIG. 6 is a top view of the battery pack of FIG. 4.

FIG. 7 is a rear perspective view of a clamp meter according to anembodiment of the invention.

FIG. 8 is a right side view of the clamp meter of FIG. 7.

FIG. 9 is a left side view of the clamp meter of FIG. 7.

FIG. 10 is a top view of the clamp meter of FIG. 7.

FIG. 11 is a bottom view of the clamp meter of FIG. 7.

FIG. 12 is a front view of the clamp meter of FIG. 7.

FIG. 13 is a rear view of the clamp meter of FIG. 7.

FIG. 14 is a front perspective view of a secondary battery lockaccording to an embodiment of the invention.

FIG. 15 is a rear view of the secondary battery lock of FIG. 14.

FIG. 16 is a top view of the secondary battery lock of FIG. 14.

FIG. 17 is a front view of a secondary battery lock according to anotherembodiment of the invention.

FIG. 18 is a perspective view of a secondary battery lock according toanother embodiment of the invention.

FIG. 19 is a rear perspective view of a clamp meter jaw mechanismaccording to an embodiment of the invention.

FIG. 20 is a top view of the clamp meter jaw mechanism of FIG. 19.

FIG. 21 is a side view of the clamp meter jaw mechanism of FIG. 19.

FIG. 22 is a block diagram of the clamp meter of FIG. 7.

FIG. 23 is a rear perspective view of an infrared (“IR”) thermometeraccording to an embodiment of the invention.

FIG. 24 is a front view of the IR thermometer of FIG. 23.

FIG. 25 is a right side view of the IR thermometer of FIG. 23.

FIG. 26 is a left side view of the IR thermometer of FIG. 23.

FIG. 27 is a rear view of the IR thermometer of FIG. 23.

FIG. 28 is a top view of the IR thermometer of FIG. 23.

FIG. 29 is a bottom view of the IR thermometer of FIG. 23.

FIG. 30 illustrates a control section of the IR thermometer of FIG. 23.

FIG. 31 is an exploded view of the IR thermometer of FIG. 23.

FIG. 32 is a block diagram of an IR thermometer according to anembodiment of the invention.

FIG. 33 illustrates a process for operating an IR thermometer accordingto an embodiment of the invention.

FIG. 34 illustrates a perspective view of a wall scanner according anembodiment of the invention.

FIG. 35 illustrates a top view of the wall scanner of FIG. 34.

FIG. 36 illustrates a front view of the wall scanner of FIG. 34.

FIG. 37 illustrates a side view of the wall scanner of FIG. 34.

FIG. 38 illustrates an exploded view of the wall scanner of FIG. 34.

FIG. 39 illustrates an exploded view of a lower portion of the wallscanner of FIG. 34.

FIG. 40 illustrates an exploded view of a side portion of the wallscanner of FIG. 34.

FIG. 41 illustrates an exploded view of a control section and a displayaccording to an embodiment of the invention.

FIG. 42 is a block diagram of a wall scanner according to an embodimentof the invention.

FIG. 43 illustrates a control section of a wall scanner according to anembodiment of the invention.

FIG. 44 illustrates a plurality of display screens of a wall scanneraccording to an embodiment of the invention.

FIG. 45 illustrates a plurality of display screens of a wall scanner ina stud scanning mode according to an embodiment of the invention.

FIG. 46 illustrates a plurality of display screens of a wall scanner ina metal scanning mode according to an embodiment of the invention.

FIG. 47 illustrates a control process for a wall scanner according to anembodiment of the invention.

DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways.

Test and measurement devices (e.g., wall scanners, thermometers, digitalmultimeters (“DMMs”), clamp meters, etc.) and other non-motorizedsensing tools are generally lightweight and low-power consumptiondevices which are powered by one or more alkaline batteries. Removableand rechargeable batteries (e.g., nickel-cadmium (“NiCd”) ornickel-metal hydride (“NiMH”) batteries), such as those used in powertools, cannot reasonably be used with test and measurement devicesbecause of the batteries' size and weight. However, lithium-ion batterypacks enable the use of high-voltage removable and rechargeable batterypacks with these non-motorized sensing tools.

As a result of the test and measurement devices receiving operationalpower from battery packs with lithium-based chemistries, the devices arecapable of including a variety of features or functions in addition totheir traditional features and functions, which increase the powerdemand of the devices. For example, a clamp meter can include ahigh-intensity LED flashlight, a non-contact voltage detector, athermocouple, a backlighted control section or actuators, ahigh-resolution LCD, a color LCD, and/or an additional or remotedisplay. Conventionally powered clamp meters (e.g., clamp meters poweredby alkaline batteries) are either unable to provide the required voltageand current to power these additional features, or the operationalruntime (i.e., the amount of time for which the batteries can power theclamp meter before the batteries need to be replaced or recharged) ofthe alkaline batteries is shortened. In contrast, the lithium-basedbattery packs are capable of powering the additional features of theclamp meter as well as the traditional features and functions, whilemaintaining an operational runtime that is comparable to or longer thana conventional clamp meter that does not include additional features.Additional test and measurement devices, such as infrared (“IR”)thermometers and wall scanners, are also able to include additionalfeatures and functions when powered by the lithium-based battery packs.

An embodiment of the invention is described with respect to a handle fora test and measurement device, such as the handle 10 illustrated inFIGS. 1, 2, and 3. The handle 10 is a pistol-grip handle and includes anouter casing 15 and a plurality of recesses. The outer casing 15includes, for example, a first half 20 and a second half 25. The firstand second halves 20 and 25 of the outer casing 15 are fixedly attachedto one another in, for example, a clamshell configuration. The firsthalf 20 and the second half 25 form the plurality of recesses whencoupled to one another. In other embodiments, the handle 10 is molded asa single piece. A first recess 30 includes a mating interface, such as,for example, rails or a mating groove (not shown) for slidably receivingan attachment, such as the battery pack. A second recess 35 isconfigured to receive a control device, such as, for example, a triggeror a knob for controlling at least a portion of the operation of thedevice. In other embodiments of the invention, more or fewer recessesare included. The handle 10 is further configured to ergonomicallyconform to the shape of a user's hand (right or left) such that thedevice can be held and operated using a single hand without the userhaving to divert his or her line-of-sight, as described below.

The handle 10 is configured to offset a holding position of the deviceto align a display, the control device, and the operation of the devicewith the user's line-of-sight or a first axis 40. The handle 10 isattached to a lower portion of a main body of the device along a secondaxis 45 such that the handle 10 is at an oblique angle with respect tothe first axis 40. In other embodiments, the handle 10 is approximatelyperpendicular to the main body. The battery pack is inserted into thefirst recess 30 and along the second axis 45 of the handle 10 to providepower to the test and measurement device.

An embodiment of a lithium-based battery pack for powering the test andmeasurement device is illustrated in FIGS. 4, 5, and 6. In theillustrated embodiment, the battery pack 100 includes battery cellshaving a lithium-based chemistry such that the battery pack 100 is over65% lighter and 50% smaller than an equivalent nickel-cadmium (“NiCd”)battery pack. The lithium-ion battery pack 100 also provides a longeroperational run-time for the test and measurement device, and a longerlife (e.g., number of recharge cycles) than the other non-lithium-basedbattery packs.

The illustrated battery pack 100 includes a casing 105, an outer housing110 coupled to the casing 105, and a plurality of battery cells 115 (seeFIG. 5) positioned within the casing 105. The casing 105 is shaped andsized to fit within the recess 30 in the device to connect the batterypack 100 to the device. The casing 105 includes an end cap 120 tosubstantially enclose the battery cells 115 within the casing 105. Theillustrated end cap 120 includes two power terminals 125 configured tomate with corresponding power terminals of the device. In otherembodiments, the end cap 120 may include terminals 125 that extend fromthe battery pack 100 and are configured to be received in receptaclessupported by the device. The end cap 120 also includes sense orcommunication terminals 130 (see FIG. 6) that are configured to matewith corresponding terminals from the device. The terminals 130 coupleto a battery circuit (not shown). The battery circuit can be configuredto monitor various aspects of the battery pack 100, such as packtemperature, pack and/or cell state of charge, etc. and can also beconfigured to send and/or receive information and/or commands to and/orfrom the device. In one embodiment, the battery circuit operates asillustrated and described in U.S. Pat. No. 7,157,882 entitled “METHODAND SYSTEM FOR BATTERY PROTECTION EMPLOYING A SELECTIVELY-ACTUATEDSWITCH,” issued Jan. 2, 2007, the entire contents of which are herebyincorporated by reference. In another embodiment, the battery circuitoperates as illustrated and described in U.S. Pat. No. 7,589,500entitled “METHOD AND SYSTEM FOR BATTERY PROTECTION,” issued Sep. 15,2009, the entire contents of which are also hereby incorporated byreference.

The casing 105 and power terminals 125 substantially enclose and coverthe terminals of the device when the pack 100 is positioned in therecess 30. That is, the battery pack 100 functions as a cover for therecess 30 and terminals of the device. Once the battery pack 100 isdisconnected from the device and the casing is removed from the recess30, the battery terminals on the device are generally exposed to thesurrounding environment.

The outer housing 110 is coupled to an end of the casing substantiallyopposite the end cap 120 and surrounds a portion of the casing 105. Inthe illustrated construction, when the casing 105 is inserted into orpositioned within the corresponding recess 30 in the device, the outerhousing 110 generally aligns with an outer surface of the handle. Inthis construction, the outer housing 110 is designed to substantiallyfollow the contours of the device to match the general shape of thehandle. In such embodiments, the outer housing 110 generally increases(e.g., extends) the length of the handle 10 of the test and measurementdevice.

In the illustrated embodiment, two actuators 135 (only one of which isshown) and two tabs 140 are formed in the outer housing 110 of thebattery pack 100. The actuators 135 and the tabs 140 define a couplingmechanism for releasably securing the battery pack 100 to the device.Each tab 140 engages a corresponding recess formed in the device tosecure the battery pack 100 in place. The tabs 140 are normally biasedaway from the casing 105 (i.e., away from each other) due to theresiliency of the material forming the outer housing 110. Actuating(e.g., depressing) the actuators 135 moves the tabs 140 toward thecasing 105 (i.e., toward each other) and out of engagement with therecesses such that the battery pack 100 may be pulled out of the recess30 and away from the device. The device also includes a secondarybattery lock (described below) which must be released before the batterypack 100 can be removed from the device. In other embodiments, thebattery pack 100 may include other suitable coupling mechanisms toreleasably secure the battery pack 100 to the device, as discussedbelow.

As shown in FIG. 5, the battery pack 100 includes three battery cells115 positioned within the casing 105 and electrically coupled to theterminals 125. The battery cells 115 provide operational power (e.g., DCpower) to the test and measurement device. In the illustratedembodiment, the battery cells 115 are arranged in series, and eachbattery cell 115 has a nominal voltage of approximately four-volts(“4.0V”), such that the battery pack 100 has a nominal voltage ofapproximately twelve-volts (“12V”). The cells 115 also have a capacityrating of approximately 1.4 Ah. In other embodiments, the battery pack100 may include more or fewer battery cells 115, and the cells 115 canbe arranged in series, parallel, or a serial and parallel combination.For example, the battery pack 100 can include a total of six batterycells 115 in a parallel arrangement of two sets of threeseries-connected cells. The series-parallel combination of battery cells115 creates a battery pack 100 having a nominal voltage of approximately12V and a capacity rating of approximately 2.8 Ah. In other embodiments,the battery cells 115 may have different nominal voltages, such as, forexample, 3.6V, 3.8V, 4.2V, etc., and/or may have different capacityratings, such as, for example, 1.2 Ah, 1.3 Ah, 2.0 Ah, 2.4 Ah, 2.6 Ah,3.0 Ah, etc. In other embodiments, the battery pack 100 can have adifferent nominal voltage, such as, for example, 10.8V, 14.4V, etc. Inthe illustrated embodiment, the battery cells 115 are lithium-ionbattery cells having a chemistry of, for example, lithium-cobalt(“Li—Co”), lithium-manganese (“Li—Mn”), or Li—Mn spinel. In otherembodiments, the battery cells 115 may have other suitable lithium orlithium-based chemistries.

Another embodiment of the invention is described with respect to a clampmeter 200 as illustrated in FIGS. 7-13. The clamp meter 200 includes,among other things, the handle 10 described above, a clamp 205, a mainbody 210, an embedded display 215, a plurality of control buttons 220,electrical terminals or leads 225, an aperture for a secondary batterylock 230 (see FIG. 12), a control device or trigger 235, a jaw mechanism(see FIG. 9), a flashlight 237, and a non-contact voltage detector (notshown). The handle 10 is also operable to receive the battery pack 100.The clamp meter 200 is operable to measure various electrical propertiesor characteristics of circuit elements such as wires, resistors,capacitors, and the like.

The clamp 205 is attached to a front portion 240 of the main body 210along the first axis 40 such that the handle 10 also forms an obliqueangle with respect to the clamp 205. The clamp 205 supports and enclosesa magnetic core for measuring current flowing through an object ormedium (e.g., a wire). The clamp 205 allows a user to measure, forexample, the electrical current flowing through the circuit elementwithout disconnecting the element from the corresponding circuit. Whenthe clamp 205 is opened, a conductor (e.g., a wire) is positioned withinan opening defined by the clamp 205 such that the magnetic coresubstantially surrounds the wire. When the clamp 205 is closed, analternating current flowing through the conductor induces a current inthe clamp 205.

The display 215 is attached to a rear portion 245 of the main body 210along the first axis 40. The user's line-of-sight is aligned with orparallel to the first axis 40. In the illustrated embodiment, thedisplay 215 is a liquid crystal display (“LCD”), such as a negative LCD(“NLCD”) with an electroluminescent backlight, but may alternatively beanother suitable type of display. The negative LCD includes lightedsymbols, such as white alphanumeric symbols, on a black background. TheNCLD improves the visibility of the display 215 in low or poor lightingconditions, such as outdoor, dark, or dirty conditions. In someembodiments, the display 215 is at a first angle with respect to thefirst axis 40 to improve the visibility of the display 215. The display215 also includes a screen timeout period which is either preprogrammedor set by the user. If the screen timeout period is reached or lapsesand no control buttons 220 are actuated and/or no measurements aretaken, the display 215 enters a standby or power saving mode to conservepower.

The control buttons 220 are positioned proximate to the display 215, onthe handle 10, on the main body 210, or any combination thereof. Theposition and configuration of the buttons 220 allow the clamp meter 200to be controlled without the user having to divert his or herline-of-sight from the display 215 or the operation of the clamp meter200. The control buttons 220 are operable to select functions and adjustsettings of the clamp meter 200. For example, one control button 220 maybe actuated to zero the clamp meter, one control button 220 may beactuated to change the units of a displayed value (e.g., from Fahrenheitto Celsius), one control button 220 may be actuated to temporarily holdor save a displayed value, one control button 220 may be actuated todisplay minimum and maximum measured values, and one control button 220may be actuated to display only a peak or inrush value.

The clamp meter 200 also includes positive and negative terminals 225positioned on the rear portion 245 of the main body 210 substantiallyopposite the clamp 205. The terminals 225 are operable to receiveelectrical leads for probes (not shown), allowing a user to test otherelectrical characteristics or properties of a circuit. For example, theterminals 225 can be used to measure AC and DC current, AC and DCvoltages, resistance, and capacitance of various circuit elements. Insome embodiments, the terminals 225 are operable to receive a contacttemperature sensor such as a thermocouple (e.g., a K-type thermocouple).The thermocouple includes two metallic elements (e.g., a hot junctionand a cold junction) which provide differing output voltages. Thedifference between the output voltages is used to determine a contacttemperature measurement. An ambient temperature sensor (not shown) suchas a thermistor can be used in combination with a look-up table for coldjunction compensation of the thermocouple. In some embodiments, thethermocouple is operable to detect temperatures in the range of, forexample, −40° C. (−40° F.) to 400° C. (752° F.).

As shown in FIG. 10, the clamp meter 200 also includes a dial 250supported on an upper surface of the main body 210. The dial 250 iselectrically coupled to a controller and is operable to change theoperating mode (i.e., the electrical characteristic being tested) of theclamp meter 200. That is, actuating (e.g., rotating) the dial 250adjusts the electrical characteristic being measured by the clamp meter200. The electrical characteristics that the clamp meter 200 can measureinclude, for example, alternating current (“AC”), direct current (“DC”),AC voltage, DC voltage, resistance, capacitance, continuity, andtemperature. In addition, one position of the dial 250 is an offposition to interrupt current flowing from the battery pack 100 to theclamp meter 200.

In some embodiments, the clamp meter 200 includes a secondary batterylock or redundant locking mechanism or another suitable lockablestructure which prevents a user from easily removing the battery pack.For example, in one embodiment, the clamp meter 200 includes a secondarybattery lock 300, as shown in FIGS. 14-16. The secondary battery lock300 works in conjunction with the actuators and tabs of the battery pack100, and is operable to redundantly secure the battery pack 100 to theclamp meter 200. In the illustrated embodiment, the secondary batterylock 300 includes a first end 305 having ball joints 310 for pivotablycoupling the secondary battery lock 300 to the handle 10 of the clampmeter 200. The secondary battery lock 300 includes a second end 315having a flange 320 for mating with a rib, groove, spine, etc. of thebattery pack 100. The secondary battery lock 300 is positioned withinthe aperture 230 (see FIG. 12) of the handle 10, and is configured suchthat it is only releasable using a separate tool, such as a flat-headedscrewdriver or a knife. As such, the secondary battery lock 300 must beconsciously opened or brought out of engagement with the battery pack100 before the battery pack 100 can be removed. The secondary batterylock 300 also includes an arcuate central portion 325 which connects thefirst end 305 and the second end 315. The central portion 325 isconfigured to conform to the contours and curvature of the handle 10. Insome embodiments, the central portion 325 is straight and does notconform to the contours of the handle 10.

FIG. 17 illustrates a secondary battery lock 400 according to anotherembodiment. The secondary battery lock 400 is similar to the secondarybattery lock 300 described above with respect to FIGS. 14-16. However,the secondary battery lock 400 is positioned behind a surface 405 ordoor within the aperture 230 of the handle 10. In some embodiments, thesecondary battery lock 400 includes a first end having, for example,ball joints for pivotably coupling the secondary battery lock 400 to thehousing of the clamp meter. In other embodiments, the secondary batterylock 400 includes a cylindrical recess for receiving a rod, shaft, orpin. In such embodiments, the secondary battery lock 400 pivots aboutthe cylindrical recess. The secondary battery lock 400 includes a secondend having a flange for mating with a rib, groove, spine, etc. of thebattery pack. The secondary battery lock 400 also includes an arcuatecentral portion which connects the first end and the second end. Thecentral portion is configured to conform to the contours and curvatureof the handle 10.

The secondary battery lock 400 is contacted through a keyhole 410 in thesurface 405 of the handle 10. The keyhole 410 is configured such thatthe secondary battery lock 400 is only releasable using a separate tool,such as a flat-headed screwdriver or a knife. The tool is inserted intothe keyhole 410 to contact the secondary battery lock 400, the batterylock 400 is forced to pivot about the first end, and the battery lockdisengages the battery pack 100. As such, the secondary battery lock 400must be consciously opened or brought out of engagement with the batterypack 100 before the battery pack 100 can be removed.

FIG. 18 illustrates a secondary battery lock 500 according to yetanother embodiment. The secondary battery lock 500 is similar to thesecondary battery lock 300 described above with respect to FIGS. 14-16.However, the secondary battery lock 500 includes a screw 505 having afirst cam 510. The secondary battery lock 500 includes a first end 515having, for example, a cylindrical recess 520 for receiving a rod,shaft, or pin, and a first flange 525 or surface. In such embodiments,the secondary battery lock 500 pivots about the cylindrical recess 520.In other embodiments, the secondary battery lock 500 includes balljoints for pivotably coupling the secondary battery lock to the handle10. The secondary battery lock 500 includes a second end 530 having asecond flange 535 for mating with a rib, groove, spine, etc. of thebattery pack 100. The secondary battery lock 500 also includes anarcuate central portion 540 which connects the first end 515 and thesecond end 530. The central portion 540 is configured to conform to thecontours and curvature of the handle 10. The secondary battery lock 500is disengaged from the battery pack 100 by turning the screw 505 using aseparate tool, such as a screwdriver or a knife. The screw 505 isaccessed through a window in the handle 10 or a keyhole similar to thatdescribed above with respect to FIG. 17. As the screw 505 is turned, thefirst cam 510 is rotated into engagement with the first flange 525. Thefirst cam 510 forces the first flange 525 to rotate about thecylindrical recess 520 and disengage the second flange 535 from thebattery pack 100. In some embodiments, the screw 505 is spring loadedsuch that the screw 505 is caused to close or rotate the secondarybattery lock 500 into engagement with the battery pack 100 when thebattery pack 100 is inserted into a the first recess 30. Accordingly,the secondary battery lock 500 must be consciously brought out ofengagement with the battery pack 100 before the battery pack 100 can beremoved.

The trigger 235 of the clamp meter 200 is operable to control, forexample, a jaw mechanism for opening and closing the clamp 205. Thetrigger 235 is also operable to turn on the LED flashlight 237. In oneembodiment, the clamp meter 200 includes a jaw mechanism 600 asillustrated in FIGS. 19-21. The jaw mechanism 600 includes the trigger235, a conductor or switch 605, an LED flashlight circuit 610, a ram615, a first spring 620, a second spring 625, a first jaw 630, and asecond jaw 635. In the illustrated embodiment, the jaw mechanism 600 isoperable to both activate an LED flashlight 237 and open the first andsecond jaws 630 and 635. The switch 605 is a two-stage switch. Thetrigger 235 pivots about a point 640 such that a rotational motion isimparted upon the flashlight circuit 610. For example, the trigger 235is engaged a first distance to close the switch 605 and activate the LEDflashlight 237. As the trigger 235 is engaged, a terminal contact of theflashlight circuit 610 moves in the direction opposite to the motion ofthe trigger 235 and approaches the switch 605. After the trigger 235 hasbeen engaged the first distance, the terminal contact of the circuit 610contacts the switch 605 and closes an LED flashlight circuit 610. Withthe LED flashlight circuit 610 closed, a voltage provided by the batterypack 100 is applied to the terminals of the LED flashlight 237 and theLED flashlight 237 is illuminated.

As the trigger 235 is engaged further, the top portion of the trigger235 contacts the ram 615 and produces a linear motion toward the firstand second jaws 630 and 635. The ram 615 is coupled to first and secondjaw latches 655 and 660 of the first and second jaws 630 and 635,respectively. The first spring 620 and the second spring 625 are alsocoupled to first and second hooks 665 and 670, respectively, to providea resilient connection between the first and second jaws 630 and 635 andthe main body 210. After the trigger 235 has been engaged a seconddistance, the top portion of the trigger forces the ram 615 into thefirst and second jaws 630 and 635. The linear motion of the ram 615 isconverted into a rotational motion of the first and second jaws 630 and635 about first and second jaw pivot axes 675 and 680, respectively.When the trigger 235 is fully engaged, the ram 615 is fully extended,and the clamp 205 provides a maximum separation between the first andsecond jaws 630 and 635 to allow a wire or other conductor to be placedwithin the clamp 205.

After the conductor has been placed within the clamp 205, the trigger235 is released to close the first and second jaws 630 and 635. If theuser requires the LED flashlight 237 to illuminate an area enclosed bythe clamp 205 or in front of the clamp meter 200, the trigger 235 can bepartially disengaged such that the terminal contact of the LEDflashlight circuit 610 remains in contact with the switch 605 to closethe LED flashlight circuit 610. Alternatively, the trigger 235 can befully disengaged and the LED flashlight 237 is deactivated. When thefirst and second jaws 630 and 635 are closed, the magnetic core withinthe clamp 205 is closed, and an induced current can be used to measurethe current in the conductor. In some embodiments, the trigger 235 iscoupled to a geared mechanical actuator. In other embodiments, the clamp205 may be opened and closed electronically when the trigger 235 isengaged and disengaged, or a different mechanical jaw mechanism can beused.

The flashlight 237 can include an incandescent light bulb, a pluralityof light emitting diodes, or the like. In one embodiment, the LEDflashlight 237 includes three high-intensity LEDs and has an output of,for example, 250 LUX at a distance of two feet. In some embodiments ofthe invention, the output of the LED flashlight 237 is greater than 250LUX at a distance of two feet. In some embodiments, the LED flashlight237 is integral to or detachable from the clamp meter 200. In suchembodiments, the flashlight 237 includes a secondary power source thatis charged or otherwise receives power from the battery pack 100. TheLED flashlight 237 also includes a flashlight timeout period. Theflashlight timeout period can have a preprogrammed value or be set bythe user. If the flashlight timeout period is reached or lapses and theLED flashlight 237 has not been turned off, the clamp meter 200 turnsoff the LED flashlight 237 to conserve power.

The non-contact voltage detector (“NCVD”) (not shown) is positioned at abase of the clamp 205 on the main body 210. A voltage sense circuit ispositioned within the clamp meter 200 and illuminates a voltage senseindicator, such as an LED, when it detects an AC voltage. In someembodiments, all or a portion of the voltage sense circuit is includedin a clamp meter controller (described below). The voltage sense circuitis operable to detect AC voltages in the range of, for example,90V-600V. In some embodiments, the voltage sense circuit NCVD isoperable to detect AC voltages anytime the clamp meter is powered orturned on. In other embodiments, the NCVD is selectively activatableusing an NCVD control button or switch. In other embodiments, the clampmeter includes a detachable non-contact voltage detector (not shown),such as that described in U.S. Pat. No. 8,193,802, issued on Jun. 5,2012 and titled “SLIDABLY ATTACHABLE NON-CONTACT VOLTAGE DETECTOR,” theentire contents of which are hereby incorporated by reference, which isslidably attachable to the clamp meter.

FIG. 22 is a block diagram of the clamp meter 200 of FIG. 7. In additionto the components and features of the clamp meter 200 described above,the clamp meter 200 also includes a controller 700. The controller 700receives signals from the clamp 205, the NCVD 705, the electrical leadsor terminals 225, the dial 250, the control buttons 220, the trigger235, and the battery pack 100. The controller 700 processes and/orconditions the signals, and outputs the conditioned signals to, forexample, the display 215 or another indication device, such as thevoltage sense indicator. The clamp meter controller 700 includes forexample, at least one printed circuit board (“PCB”). The PCB ispopulated with a plurality of electrical and electronic components whichprovide operational control and protection to the clamp meter. In someembodiments, the PCB includes a control or processing unit such as amicroprocessor, a microcontroller, or the like. In some embodiments, thecontroller 700 includes, for example, the processing unit, a memory, anda bus. The bus connects various components of the controller 700including the memory to the processing unit. The memory includes, insome embodiments, read only memory (“ROM”) and random access memory(“RAM”). The controller 700 also includes an input/output system thatincludes routines for transferring information between components withinthe controller 700. Software included in the implementation of the clampmeter is stored in the ROM or RAM of the controller 700. The softwareincludes, for example, firmware applications and other executableinstructions. In other embodiments, the controller 700 can includeadditional, fewer, or different components.

The PCB also includes, for example, a plurality of additional passiveand active components such as resistors, capacitors, inductors,integrated circuits, and amplifiers. These components are arranged andconnected to provide a plurality of electrical functions to the PCBincluding, among other things, filtering, signal conditioning, andvoltage regulation. For descriptive purposes, the PCB and the electricalcomponents populated on the PCB are collectively referred to herein as“the controller” 700. The display 215 receives the processed andconditioned signals from the controller 700 and displays a value (e.g.,a number) corresponding to the measured current, or an indication of acontrol parameter of the clamp meter 200 (e.g., sensing mode).

In some embodiments, a battery pack controller (not shown) providesinformation to the clamp meter controller 700 related to a battery packtemperature or voltage level. The clamp meter controller 700 and thebattery pack also include low voltage monitors and state-of-chargemonitors. The monitors are used by the clamp meter controller 700 or thebattery pack controller to determine whether the battery pack isexperiencing a low voltage condition, which may prevent proper operationof the clamp meter 200, or if the battery pack is in a state-of-chargethat makes the battery pack 100 susceptible to being damaged. If such alow voltage condition or state-of-charge exists, the clamp meter 200 isshut down or the battery pack 100 is otherwise prevented from furtherdischarging current to prevent the battery pack 100 from becomingfurther depleted.

Another embodiment of the invention is described with respect to aninfrared (“IR”) thermometer. FIGS. 23-29 illustrate an IR thermometer810 that includes, among other things, a handle 815, a main body 820, anembedded display 825, a control device or trigger 830, a control section835, a grip portion 840, and a high-voltage removable and rechargeablebattery pack (described below). The handle 815 is substantially similarto the handle 10 described above with respect to FIGS. 1-3. The handleportion includes a recess that is adapted to receive the battery pack100 described above with respect to FIGS. 4-6.

The display 825 is attached to a rear portion of the main body 820 alongthe first axis 850. The user's line-of-sight is aligned with or parallelto a first axis 850. In the illustrated embodiment, the display 825 is aliquid crystal display (“LCD”), such as a negative LCD (“NLCD”) with anelectroluminescent backlight, but may alternatively be another suitabletype of display. The negative LCD includes lighted symbols, such aswhite alphanumeric symbols, on a black background. The NCLD improves thevisibility of the display 825 in low or poor lighting conditions, suchas outdoor, dark, or dirty conditions. In some embodiments, the display825 is at an offset angle with respect to the first axis 850 to improvethe visibility of the display 825. The display 825 also includes ascreen timeout period which is either preprogrammed or set by the user.If the screen timeout period is reached or lapses and no buttons in thecontrol section 835 are actuated and/or no measurements are taken, thedisplay 825 enters a standby or power saving mode to conserve power.

The control section 835 is illustrated in FIG. 30. The control section835 is positioned proximate to the display 825 and includes a pluralityof control buttons. The position and configuration of the controlbuttons allow the thermometer 810 to be controlled without the userhaving to divert his or her line-of-sight from display 825 or theoperation of the thermometer 810. For example, in the illustratedembodiment, the control section 835 is positioned below the display 825.The control section 835 includes a mode button 860, an up button 865, adown button 870, a settings button 875, a log save button 880, an alarmbutton 885, and a flashlight button 890. The mode button 860 is actuatedto select an operational mode from, for example, a menu or apredetermined set of operational modes. For example, the mode button 860allows a user to scroll through a plurality of operational modes, suchas an average temperature mode, a maximum temperature mode, a minimumtemperature mode, a humidity mode, a dew point mode, a wet bulb mode,and a contact temperature mode. In some embodiments, the mode button 860is repeatedly selected to cycle through the operational modes of thethermometer 810. In other embodiments, the mode button 860 is pressedonce, and the up and down buttons 65 and 870 are used to scroll throughthermometer 810 modes. The selected operational mode determines theinformation that is displayed on the display 825. As such, in someembodiments, the thermometer 810 is a menu-driven device. In someembodiments, the thermometer 810 also includes one or more LEDs forproviding an indication to the user of the status or operational mode ofthe thermometer 810, the battery pack, or both.

Additional control buttons can be located on the handle 815 and/or themain body 820. For example, an electronic trigger lock button 895 islocated on the handle 815 and enables the thermometer 810 to take acontinuous non-contact temperature reading without the trigger 830 beingengaged. In some embodiments, the thermometer 810 takes the non-contacttemperature reading until the user engages the trigger 830 a secondtime. In other embodiments, the continuous reading is taken until thetrigger lock button 895 is deactivated, or a predetermined time limit(e.g., 20 minutes) has elapsed.

If the thermometer 810 is operating in the average temperature mode, anindication that the thermometer 810 is operating in the averagetemperature mode is displayed on the display 825. In one embodiment, theletters “AVG” are displayed. When operating in the average temperaturemode, the average temperature during the course of a single temperaturereading (e.g., the time during which the trigger 830 is pressed) is alsodisplayed on the display 825. If the thermometer 810 is operating in themaximum temperature mode, an indication that the thermometer 810 isoperating in the maximum temperature mode is displayed on the display825. In one embodiment, the letters “MAX” are displayed. When operatingin the maximum temperature mode, the maximum temperature reading duringthe course of a single temperature reading is also displayed. If thethermometer 810 is operating in the minimum temperature mode, anindication that the thermometer 810 is operating in the minimumtemperature mode is displayed on the display 825. In one embodiment, theletters “MIN” are displayed. When operating in the minimum temperaturemode, the minimum temperature reading during the course of a singletemperature reading is also displayed on the display 825. If thethermometer 810 is operating in the humidity mode, an indication thatthe thermometer 810 is operating in the humidity mode is displayed onthe display 825. In one embodiment, the letters “HUM” are displayed, aswell as an indication that a relative humidity measurement is beingdisplayed (e.g., “RH %”). When operating in the humidity mode, athree-digit relative humidity (e.g., 96.3) is displayed. If thethermometer 810 is operating in the dew point mode, an indication thatthe thermometer 810 is operating in the dew point mode is displayed onthe display 825. In one embodiment, the letters “DEW” and a calculateddew point are displayed. If the thermometer 810 is in the wet bulb mode,an indication that the thermometer 810 is operating in the wet bulb modeis displayed. In one embodiment, the letters “WET” and a wet bulbcalculation are displayed. If the thermometer 810 is operating in thecontact temperature mode, an indication that the thermometer 810 isoperating in the contact temperature mode is displayed. In oneembodiment, the letters “CON” and a contact temperature measurement aredisplayed on the display 825.

The settings button 875 is operable to set or modify various thresholdsand functions of the thermometer 810. For example, the settings button875 is actuated to scroll through the thresholds and functions which theuser can control. For example, the settings button 875 allows a user toset a high temperature alarm threshold, a low temperature alarmthreshold, a log reading, an emissivity, and temperature measurementunits (e.g., Fahrenheit or Celsius), and turn a laser (see FIG. 31) onand off. In some embodiments, the settings button 875 is repeatedlyactuated to cycle through the thresholds and functions. In otherembodiments, the settings button 875 is actuated once, and the up anddown buttons 865 and 870 are used to scroll through thermometerthresholds and functions.

When setting the high temperature alarm threshold, the user actuates thesettings button 875 until the letters “HI” appear on the display 825.The user adjusts the high temperature alarm threshold using the up anddown buttons 865 and 870. The alarm is activated when the non-contacttemperature reading is above the high temperature alarm threshold. Whensetting the low temperature alarm threshold, the user actuates thesettings button 875 until the letters “LOW” appear on the display 825.The user adjusts the low temperature alarm threshold using the up anddown buttons 865 and 870. The alarm is activated when the non-contacttemperature reading is below the low temperature alarm threshold. Thealarm is toggled on and off using the alarm button 885. When setting alog value, the user actuates the settings button 875 until the letters“LOG” appear on the display 825. The thermometer 810 also displays anumber (e.g., between 1 and 20) which indicates a log value memorylocation. For example, if a log value was previously saved to a logvalue memory location, the previously saved log value is displayed. Theuser can scroll through the saved log values using the up and downbuttons 865 and 870. The user can overwrite the previously saved logvalue by actuating the log save button 880 when a particular log valuememory location is displayed. The user sets the emissivity of thethermometer 810 by actuating the settings button 875 until the symbol,ε, is displayed. The user adjusts the emissivity level using the up anddown buttons 865 and 870. The user toggles the laser on and off byactuating the settings button 875 until a laser symbol (e.g., a classtwo laser safety symbol) is displayed, and using the up and down buttons865 and 870 to selectively activate and deactivate the laser.

FIG. 31 illustrates an exploded view of the IR thermometer 810. Thethermometer 810 includes, among other things, the trigger lock button895, an IR temperature sensor 900, a contact temperature sensor port905, a humidity sensor 910, a buzzer 920, an LED flashlight 925, a lasermodule 935, a convex lens 940, a cylindrical aluminum tube 945, and anLCD assembly 950. The flashlight 925 is toggled on and off using theflashlight button 890 in the control section 835. The flashlight 925 caninclude an incandescent light bulb, a plurality of light emittingdiodes, or the like. In one embodiment, the LED flashlight 925 includesthree high-intensity LEDs and has an output of, for example, 250 LUX ata distance of two feet. In some embodiments of the invention, the outputof the LED flashlight 925 is greater than 250 LUX at a distance of twofeet. In some embodiments, the LED flashlight 925 is integral to ordetachable from the thermometer 810. In such embodiments, the flashlight925 includes a secondary power source that is charged or otherwisereceives power from the battery pack. The LED flashlight 925 alsoincludes a flashlight timeout period. The flashlight timeout period canhave a preprogrammed value or be set by the user. If the flashlighttimeout period is reached or lapses and the LED flashlight 925 has notbeen turned off, the thermometer 810 turns off the LED flashlight 925 toconserve power.

FIG. 32 is a block diagram of the IR thermometer 810. The thermometer810 includes a thermometer controller 1000, the IR temperature sensor900, the contact temperature sensor port 905, the humidity sensor 910,an ambient temperature sensor 1005, the control section 835, and thedisplay 825. The controller 1000 includes a plurality of differentialamplifiers 1010, a plurality of analog-to-digital converters (“ADCs”)1015, a processing module 1020, an IR temperature output 1025, a contacttemperature output 1030, a humidity output 1035, an ambient temperatureoutput 1040, a memory module 1045, an IR temperature compensation module1050, a contact temperature compensation module 1055, and a humiditycompensation module 1060. In some embodiments, the ADCs 1015 are 24-bithigh precision delta-sigma ADCs. The thermometer controller 1000 alsoincludes for example, at least one printed circuit board (“PCB”). ThePCB is populated with a plurality of electrical and electroniccomponents which provide power, operational control, and protection tothe thermometer 810. In some embodiments, the PCB includes theprocessing module 1020 which is, for example, a microprocessor. Thecontroller 1000 also includes a bus for connecting the variouscomponents and modules located within or connected to the controller1000. The memory module 1045 includes, in some embodiments, read onlymemory (“ROM”), such as electronically erasable programmable ROM(“EEPROM”), and random access memory (“RAM”). The controller 1000 alsoincludes an input/output system that includes routines for transferringinformation between components and modules within the controller 1000.Software included in the implementation of the thermometer 810 is storedin the ROM or RAM of the controller 1000. The software includes, forexample, firmware applications and other executable instructions. The IRtemperature compensation module 1050 and the contact temperaturecompensation module 1055 use output signals from the humidity sensor 910or ambient temperature sensor 1005 to compensate temperaturemeasurements and generate a compensated IR temperature output and acompensated contact temperature output. The humidity compensation module1060 uses an output from the ambient temperature sensor to compensatehumidity measurements and generate compensated humidity outputs. Inother embodiments, the controller 1000 can include additional, fewer, ordifferent components.

The PCB also includes, for example, a plurality of additional passiveand active components such as resistors, capacitors, inductors,integrated circuits, and amplifiers. These components are arranged andconnected to provide a plurality of electrical functions to the PCBincluding, among other things, sensing, filtering, signal conditioning,and voltage regulation. For descriptive purposes, the PCB and theelectrical components populated on the PCB are collectively referred toherein as “the controller” 1000. The controller 1000 receives signalsfrom the IR temperature sensor 900, the contact temperature sensor port905, the humidity sensor 910, and the ambient temperature sensor 1005;processes or conditions the signals; and transmits the processed andconditioned signals to the display 825. In some embodiments, the IRtemperature sensor 900, the contact temperature sensor port 905, and thehumidity sensor 910 are calibrated or recalibrated using the ambienttemperature signal. The display 825 receives the processed andconditioned signals and displays an indication of an IR temperaturemeasurement, a contact temperature measurement, a humidity, a dew point,or the like to the user.

In some embodiments, a battery pack controller (not shown) providesinformation to the thermometer controller 1000 related to a battery packtemperature or voltage level. The thermometer controller 1000 and thebattery pack also include low voltage monitors and state-of-chargemonitors. The monitors are used by the thermometer controller 1000 orthe battery pack controller to determine whether the battery pack 100 isexperiencing a low voltage condition, which may prevent proper operationof the thermometer 810, or if the battery pack is in a state-of-chargethat makes the battery pack susceptible to being damaged. If such a lowvoltage condition or state-of-charge exists, the thermometer 810 is shutdown or the battery pack 100 is otherwise prevented from furtherdischarging current to prevent the battery pack from becoming furtherdepleted.

The IR temperature sensor 900 is, for example, a thermopile. Thethermopile includes a plurality of thermoelements (e.g., thermocouples)connected in series to form a sensing area or detector, and the sensingarea is covered with an IR-absorbing material. A lens focuses infraredenergy onto the detector, and the thermopile outputs a signal which isdirectly proportional to the power of the infrared radiation incidentupon the detector. In some embodiments, the IR temperature sensor 900 isoperable to sense temperatures in the range of, for example, −30° C.(−22° F.) to 800° C. (1472° F.). The contact temperature sensor port 905is, for example, a thermocouple port and is operable to receive athermocouple, such as a K-type thermocouple. The combination of thethermocouple and the thermocouple port are referred to herein as thethermocouple 905. The thermocouple 905 includes two metallic elements(e.g., a hot junction and a cold junction) which provide differingoutput voltages. The difference between the output voltages is used todetermine a contact temperature measurement. The ambient temperaturesensor 1005 (e.g., a thermistor) is used in combination with a look-uptable for cold junction compensation of the thermocouple 905. In someembodiments, the thermocouple 905 is operable to detect temperatures inthe range of, for example, −40° C. (−40° F.) to 550° C. (1022° F.). Thethermocouple may be used independently of the temperature sensor. Assuch, an output of the thermocouple 905 is not used to compensate orotherwise modify an output of the thermopile. The thermopile is operableto sense a first temperature of a first area in a non-contact manner,and the thermocouple 905 is operable to sense a second temperature of asecond area in a contact manner. In some embodiments, the first area andthe second are located on the same object or surface, and thethermocouple 905 can be used in conjunction with the IR temperaturesensor 900 to provide, for example, both contact and non-contacttemperature measurements of an object. In other embodiments, the firstarea is located on a first object, and the second area is located on asecond object.

The humidity sensor 910 provides a signal to the controller 1000 that isindicative of the humidity in the environment surrounding thethermometer 810. The humidity sensor 910 is for example, a resistivehygrometer which uses a polymer membrane which has a conductivity thatvaries with the amount of water it absorbs. The humidity sensor 910 isused for calibrating the IR temperature sensor 900 and for compensatingmeasurements made using the IR temperature sensor 900 and thethermocouple 905. In some embodiments, the humidity is displayed on thedisplay 825.

The thermometer 810 also includes a distance-to-spot ratio (“D:S”). TheD:S ratio is a ratio of a distance to an object and a diameter of atemperature measurement area (i.e., a spot size). For example, if theD:S is 20:1, the IR temperature sensor 900 averages the temperature ofan object twenty feet away over an area with a one-foot diameter. Thefarther the IR temperature sensor 900 is from the object, the larger thespot size. In some embodiments, the IR temperature sensor 900 includessettings for measuring the temperature of both reflective andnon-reflective surfaces.

In some embodiments, the thermometer 810 also includes a distance meter(not shown). The distance meter is, for example, a laser distance meter.The distance meter uses a time-of-flight of a light pulse or anultrasonic wave to determine a distance to the object. The distancemeter measures the time-of-flight required for the light pulse or theultrasonic wave to travel to the object and back. Based on thetime-of-flight and a known speed of light (or sound), the distance tothe object is calculated. In other embodiments of the invention,different techniques are used to determine the distance to the objectsuch as a multiple frequency phase-shift technique.

The spot size is calculated using the D:S ratio of the IR temperaturesensor 900 and a distance measurement from the distance meter. Forexample, the distance meter and the IR temperature sensor 900 arealigned along an axis such that the distance meter and the temperaturesensor are approximately the same distance from the object. The distancemeter uses a single beam of light to determine the distance from thethermometer 810 to the object. The thermometer 810 uses the distancemeasurement from the distance meter and the D:S ratio to calculate thediameter of a measurement area on the object. The thermometer 810 thendisplays, for example, a numerical representation of the spot size, anarea of the spot, or both. In other embodiments, a visual representationof the measurement area and/or the spot size is displayed.

FIG. 33 illustrates a process 1100 for taking a temperature measurementusing the thermometer 810. The thermometer 810 first determines whetherthe battery pack 100 is experiencing a low-voltage condition (step1105). If the battery pack 100 is in a low-voltage condition, alow-battery warning is initiated (step 1110). In some embodiments, thelow-battery warning is displayed on the display 825. In otherembodiments, an LED is lighted or a buzzer is sounded to provide thelow-battery warning. If no low-voltage condition exists, the thermometer810 is operable to make temperature measurements. A default operationaland display mode for the thermometer 810 is the non-contact temperaturemeasurement mode. To take an IR temperature measurement (step 1115), theuser engages the trigger 830. Temperature measurements are taken as longas the trigger 830 is engaged. Alternatively, if the electronic triggerlock button 895 is engaged, a continuous temperature measurement can betaken without continuously engaging the trigger 830. The thermometer 810then determines whether a thermocouple 905 is present (step 1120). If athermocouple 905 is present, a contact temperature measurement is taken(step 1125) and the relative humidity is measured using the humiditysensor 910 (step 1130). If no thermocouple 905 is present, thethermometer 810 measures the relative humidity using the humidity sensor910 (step 1130). The thermometer 810 then determines whether themeasured IR temperature is greater than the high-temperature alarmthreshold or below the low temperature alarm threshold (step 1135). Ifthe measured IR temperature is outside of the high and low thresholdvalues, a temperature range warning is initiated (step 1140). In someembodiments, the temperature range warning is displayed on the display825. In other embodiments, an LED is lighted or a buzzer is sounded toprovide the temperature range warning. If the measured IR temperature isnot greater than the high temperature alarm threshold or less than thelow temperature alarm threshold, the measured temperature is displayedon the display 825 (step 1145).

Another embodiment of the invention is described with respect to a wallscanner that is capable of detecting a plurality of objects hiddenbehind a plurality of different surfaces. The wall scanner includes ahousing, a plurality of sensors, a display, a control section, and aplurality of wheels. The housing includes a body portion and a handleportion similar to the handle 10 described above with respect to FIGS.1-3. The handle portion includes a recess that is adapted to receive thebattery pack 100 described above with respect to FIGS. 4-6.

FIGS. 34-41 illustrate the wall scanner 1205 and housing 1210 accordingto an embodiment of the invention. A handle portion 1215 of the wallscanner housing 1210 includes a battery pack recess 1220 (see FIG. 38)adapted to receive the battery pack 100. The battery pack recess 1220includes a plurality of terminals (shown as 1345 in FIG. 40) forelectrically connecting the battery pack 100 to the wall scanner 1205.Additionally, the handle portion 1215 includes a plurality of recessedgripping portions 1235 that provide additional grip to a user.

The handle portion 1215 and the battery pack 100 define a first axis1241 of the wall scanner 1205. The handle portion 1215 is coupled to andextends from the body portion 1240 of the wall scanner 1205 such that arecess 1245 is formed between the body portion 1240 and the handleportion 1215. The extension of the handle portion 1215 from the bodyportion 1240 allows the wall scanner 1205 to receive the battery pack100. In some embodiments, the recess 1245 between the handle portion1215 and the body portion 1240 is closed by first and second connectingportions 1250 and 1255. In other embodiments, the recess 1245 is openand includes a single connecting portion. The recess 1245 defines aspace for accommodating the fingers of a user while the user is holdingthe wall scanner 1205.

The handle portion 1215 extends approximately half the length of thehousing 1210 and is approximately parallel to the body portion 1240 anda display 1260. In one embodiment, the first axis 1241 is parallel to asecond axis 1243 which extends through a center of the body portion1240. In other embodiments, the first axis 1241 is not parallel to thesecond axis 1243, and the first axis 1241 intersects the second axis1243 at a point a distance, d, away from the wall scanner 1205. Thedisplay 1260 is positioned on the body portion 1240 such that thedisplay 1260 is not blocked by the user's hand when the wall scanner1205 is being gripped. The control section 1265 is provided on the firstconnecting portion 1250 between the body portion 1240 and the handleportion 1215 of the wall scanner 1205. The control section 1265 ispositioned at an oblique angle with respect to the body portion 1240 ofthe housing such that the buttons or switches (described below) withinthe control section 1265 can be activated by the user using the samehand with which the user is gripping the wall scanner 1205. In someembodiments, the wall scanner 1205 also includes one or more LEDs forproviding an indication to the user of the status of the wall scanner1205, the battery pack 100, or both. The wheels 1270 are rotatablycoupled to the housing 1210 to facilitate movement of the wall scanner1205 along a surface. In the illustrated embodiment, the wheels 1270 areidle wheels, but may alternatively be driven wheels that are powered bythe battery pack 100.

FIG. 38 illustrates an exploded view of the wall scanner 1205 shown inFIGS. 34-41. The wall scanner 1205 includes a base housing assembly1300, right and left housing assemblies 1305 and 1310, a panel assembly1315, and the battery pack 100. An exploded view of the base housingassembly 1300 is shown in FIG. 39. The base housing assembly 1300includes a main printed circuit board assembly (“PCB”) 1320, a sensorboard 1325 which includes plate sensors for sensing studs, a D-coilsensor 1330 for sensing metal, a base 1335, and the wheels 1270. Anexploded view of the right housing assembly 1305 is shown in FIG. 40.The left housing assembly 1310 is similar to the right housing assembly1305 and is not described in detail. The right housing assembly 1305includes contact plate terminals 1345, a battery contact PCB 1350, aright half of the housing 1355, an indicator lens 1360, and an LED 1365.An exploded view of the panel assembly 1315 is shown in FIG. 41. Thepanel assembly 1315 includes a keypad 1370, a key holder 1375, a rubberkey 1380, a light guide 1385, a key PCB 1390, a key panel 1395, an LCDlens 1400, and an LCD assembly 1405.

FIG. 42 is a block diagram of a wall scanner 1205 according to anembodiment of the invention. The wall scanner 1205 includes a mainsystem module 1415, the stud sensor 1325, the D-coil sensor 1330, andthe display 1260. The main system module 1415 includes, among otherthings, a wall scanner controller 1420, a signal conditioning module1425, a peak detection module 1430, and an analog-to-digital conversionmodule 1435. The display 1260 is, for example, a 128×64 dot matrixliquid crystal display (“LCD”) or negative LCD (“NLCD”). The wallscanner controller 1420 includes, for example, a PCB such as PCB 1320shown in FIG. 39. The PCB 1320 is populated with a plurality ofelectrical and electronic components which provide operational controland protection to the wall scanner 1205. In some embodiments, the PCB1320 includes a control or processing unit such as a microprocessor, amicrocontroller, or the like. In some embodiments, the controller 1420includes, for example, the processing unit, a memory, and a bus. The busconnects various components of the controller 1420 including the memoryto the processing unit. The memory includes, in many instances, readonly memory (“ROM”) and random access memory (“RAM”). The controller1420 also includes an input/output system that includes routines fortransferring information between components within the controller 1420.Software included in the implementation of the wall scanner 1205 isstored in the ROM or RAM of the controller 1420. The software includes,for example, firmware applications and other executable instructions. Inother embodiments, the controller 420 can include additional, fewer, ordifferent components.

The PCB 1320 also includes, for example, a plurality of additionalpassive and active components such as resistors, capacitors, inductors,integrated circuits, and amplifiers. These components are arranged andconnected to provide a plurality of electrical functions to the PCB 1320including, among other things, filtering, signal conditioning, andvoltage regulation. For descriptive purposes, the PCB 1320 and theelectrical components populated on the PCB 1320 are collectivelyreferred to herein as “the controller” 1420. The controller 1420receives signals from the sensors within the wall scanner, conditionsand processes the signals, and transmits processed and conditionedsignals to the display 1260. The display 1260 receives the processed andconditioned signals and displays an indication of a sensedcharacteristic of an object hidden behind a surface. The signalconditioning module 1425 provides signals to and receives signals fromthe stud sensor 1325, as described below; the peak detection module 1430receives signals from and sends signals to the D-coil sensor 1330, asdescribed below; and the analog-to-digital conversion module 1435provides the conversion necessary for the controller 1420 to interpretanalog signals from the D-coil sensor 1330.

In some embodiments, a battery pack controller (not shown) can provideinformation to the wall scanner controller 1420 related to a batterypack temperature or voltage level. The wall scanner controller 1420 andthe battery pack controller also include low voltage monitors andstate-of-charge monitors. The monitors are used by the wall scannercontroller 1420 or the battery pack controller to determine whether thebattery pack 100 is experiencing a low voltage condition which mayprevent proper operation of the wall scanner 1205, or if the batterypack 100 is in a state-of-charge that makes the battery pack 100susceptible to being damaged. If such a low voltage condition orstate-of-charge exists, the wall scanner 1205 is shut down or thebattery pack 100 is otherwise prevented from further discharging currentto prevent the battery pack 100 from becoming further depleted.

The wall scanner 1205 is operable to detect the presence of a stud, suchas a wood stud or metal joists within residential, commercial, andindustrial structures using the stud sensor 1325. The wooden studs ormetal joists can be detected when hidden behind surfaces composed of,for example, plaster, non-metallic wall materials, wooden panels, wallboard, and the like. The stud sensor 1325 includes a sensor circuit witha pair of sensors. Each sensor includes a coplanar primary plate 1440Awith a single side coplanar plate 1440B arranged between the primaryplates. The presence and location of the stud is then determined in amanner similar to that described in U.S. Pat. No. 7,504,817, titled“STUD SENSOR,” issued on Mar. 17, 2009, the entire contents of which arehereby incorporated by reference.

The wall scanner 1205 is also configured to operate in a metal scanningmode. The metal scanning mode is operable to detect both ferrous (i.e.,iron based) and non-ferrous (e.g., copper) metals within residential,commercial, and industrial structures. While in the metal scanning mode,the wall scanner 1205 can detect metal (e.g., rebar, metal conduit,copper piping, etc.) behind surfaces composed of wall board, tile,plaster, brick, or the like. The wall scanner 1205 can also detect metalwithin walls composed of concrete, masonry, wood, brick, or the like. Insome embodiments, the wall scanner 1205 is operable to sense metal to adepth of, for example, six inches.

The D-coil sensor 1330 illustrated in FIG. 39 uses an inductivelycoupled sensor that includes overlapping D-shaped transmitter andreceiver coils 1445A and 1445B. When the D-coil sensor 1330 detects ametallic object, the sensor 1330 outputs a signal to the controller 1420indicating the location of the object. The wall scanner 1205 detects thepresence of metal in a manner similar to that described in U.S. Pat. No.7,977,938, titled “DEVICE AND METHOD OF DETECTING FERRITE ANDNON-FERRITE OBJECTS,” issued Jul. 12, 2011, the entire contents of whichare hereby incorporated by reference.

The wall scanner 1205 is also configured to detect the presence of“live” (i.e., energized) electrical wiring behind a surface. In someembodiments, the wall scanner 1205 includes an AC detection circuit suchas that described in U.S. Pat. No. 6,894,508, titled “APPARATUS ANDMETHOD FOR LOCATING OBJECTS BEHIND A WALL LINING,” the entire contentsof which are hereby incorporated by reference. In other embodiments, thewall scanner 1205 includes a detachable non-contact voltage detector(not shown), such as that described in co-pending U.S. Pat. No.8,193,802 entitled “SLIDABLY ATTACHABLE NON-CONTACT VOLTAGE DETECTOR,”issued Jun. 5, 2012, the entire contents of which were previouslyincorporated by reference, which is slidably attachable to the housing1210 of the wall scanner 1205. The wall scanner 1205 includes the LED1365 for indicating the detection of an AC voltage. The LED 1365 can belocated at a first end of the wall scanner 1205, such as the endopposite the battery pack 100 (as shown in FIG. 40), on the display1260, or both. The wall scanner 1205 is operable to sense the presenceof AC voltages regardless of the operational mode of the wall scanner1205 (e.g., metal sensing mode or stud sensing mode), and the wallscanner 1205 does not need to be calibrated to detect the presence of ACvoltages.

FIG. 43 illustrates the control section 1265 of the wall scanner 1205.The control section 1265 is positioned between the display 1260 and thehandle portion 1215 along the first axis 1241. The control section 1265includes buttons, switches, or other actuation devices for controllingthe function and operation of the wall scanner 1205. In someembodiments, the control section 1265 includes a metal sensing modebutton 1500, a stud sensing mode button 1505, a menu button 1510, apower button 1515, and a calibration button 1520. In other embodiments,the control section 1265 includes additional buttons or switches forcontrolling additional or different features or functions of the wallscanner 1205. One or more of the buttons included in the control section1265 may have multiple functions such as selecting an operational modeand enabling a user to scroll through menu options on the display 1260.In the illustrated embodiment of the control section 1265, the buttonsare arranged in a circular manner. In other embodiments, the buttons inthe control section 1265 can be arranged in a variety of differentconfigurations, such as a grid or an array. In various embodiments ofthe control section 1265, the buttons are configured such that a usercan access and select each button using a single hand (e.g., the samehand the user is using to grip the handle portion of the wall scanner).

The display 1260 is symmetrically aligned along the first axis 1241defined by the handle portion 1215 and the battery pack 100. The display1260 is configured to display a plurality of status indications relatedto the operation of the wall scanner 1205. For example, the display 1260can display, among other things, the operational mode of the wallscanner 1205, the location of an object hidden behind the surface inreal-time, the depth of an object hidden behind the surface, whether anobject hidden behind the surface is ferrous or non-ferrous, battery packpower level, and an indication of whether sound (i.e., audibleindication) is turned on or off. FIGS. 44-46 illustrate embodiments ofwall scanner status indications that the display 1260 is configured todisplay.

The controller 1420 receives signals from the sensors, processes orconditions the signals, and transmits the conditioned signals to thedisplay 1260, as described above. The display 1260 receives theconditioned signals and displays an image, a value (e.g., a distance,coordinates, etc.), an alert relating to the detected object, testresults, measurement values, properties of the wall scanner, etc. Thedisplay 1260 includes lighted symbols, such as white alphanumericsymbols, on a black background. The display 1260 improves the visibilityof the display in low or poor lighting conditions, such as outdoor,dark, or dirty conditions. Additionally or alternatively, the wallscanner 1205 can include a remote display (not shown) that can beattachable to or detachable from the wall scanner 1205 to provide theuser with a remote display of the detection and/or position of a stud,or the operation of the wall scanner 1205. The wall scanner 1205 caninclude a transmitter and a receiver for communicating with the remotedisplay. In some embodiments, the remote display is configured todisplay the same information as the display 1260.

The user can access a menu (screen 1600) on the display 1260 byactivating buttons in the control section 1265. From the menu, a list ofoptions relating to various settings of the wall scanner 1205 isdisplayed on the display 1260. The user is able to select betweenEnglish and metric units for displaying the depth or location of anobject (screen 1605). The user can also select whether sound isactivated (screen 1610). When sound is activated, the wall scanner 1205produces, for example, a beep or a series of beeps to indicate thepresence or depth of an object hidden behind a surface. In otherembodiments, the menu is operable to control additional functions suchas display screen brightness, turning a backlight on and off,controlling the operation of a remote display, and adjusting wallscanner sensitivities. As such, the wall scanner 1205 is a menu-drivendevice.

The display 1260 also provides instructions to the user for calibratingthe wall scanner 1205 after power-up. When the wall scanner 1205 isoperating in the stud sensing mode, the user is prompted to place thewall scanner 1205 on the surface to be scanned and activate thecalibration button 1520 (screen 1615). The display 1260 then indicatesto the user that the wall scanner 1205 is being calibrated (screen1620). The user can, if desired, manually change the sensitivity (e.g.,scan depth) of the wall scanner 1205. For example, in one embodiment, adefault depth setting of 0.5 inches is set for the wall scanner 1205when in the stud sensing mode. To change the scanning depth, the useractivates the calibration button 1520 while the wall scanner 1205 iscalibrating. Activating the calibration button 1520 a second timechanges the scanning depth from 0.5 inches to 1.0 inches. Activating thecalibration button 1520 a third time changes the scanning depth from 1.0inches to 1.5 inches. If the calibration button is activated a fourthtime, the scanning depth cycles back to 0.5 in. In other embodiments,the wall scanner 1205 is configured with different scanning depths andsensitivities. If an error occurs during calibration, the user isprompted with an error message, such as that shown in screen 1625.

After calibration, the display 1260 indicates when the wall scanner 1205is scanning for a stud (screen 1630). The display 1260 is configured todisplay the location of a detected stud in real-time as the wall scanner1205 is passing over the stud. For example, when the wall scanner 1205is moving from left to right across a surface and a stud is detected,the stud is identified by a partially illuminated portion of the display1260 (e.g., the stud is represented by a combination of illuminatedpixels and non-illuminated pixels). The illuminated pixels form aplurality of lines such as horizontal lines, vertical lines, diagonallines, or any combination thereof which are separated by non-illuminatedpixels or lines. The display 1260 also includes a visual and/orlinguistic identification of the edge of the stud (e.g., an arrow and/orthe word “edge” displayed on the wall scanner display), as shown inscreen 1635. The display 1260 can also display both edges of a stud ifthe width of the stud is not greater than the width of the display 1260.In such an instance, each edge is identified by an arrow and/or alinguistic identification, and the stud is represented by a combinationof illuminated and non-illuminated portions (screen 1640). The wallscanner 1205 includes similar visual representations of a stud'slocation in real-time when the wall scanner is moving from the right tothe left (screen 1645).

When the wall scanner 1205 is operating in the metal sensing mode, theuser is prompted to hold the wall scanner 1205 off of the surface to bescanned in order for the wall scanner 1205 to be properly calibrated(screen 1650). Similar to the stud sensing mode, the wall scanner 1205provides an indication on the display that the wall scanner 1205 isbeing calibrated (screen 1655). If an error occurs during calibration,the user is prompted with an error message, such as that shown in screen1660. After calibration, the display 1260 indicates when the wallscanner 1205 is scanning for metal (screen 1665). If the wall scanner1205 detects the presence of metal, the user is prompted visually oraudibly that metal has been detected (screen 1670). The display 1260then provides the user with an indication of whether the detected metalis ferrous or non-ferrous, a numerical indication of the depth of thedetected object, and a visual indication of the depth of the object(screen 1675). In some embodiments of the invention, the display 1260can also provide a symbol to indicate the nearest distance to a detectedmetal object (screen 1680).

A process 1700 for the general operation of the wall scanner 1205 isillustrated in FIG. 47. After the wall scanner 1205 is powered up (step1705), the default sensing mode for the wall scanner 1205 is the metalsensing mode. To use the wall scanner in the metal sensing mode, theuser activates the calibration button 1520 from the control section 1265(step 1710). If the wall scanner 1205 calibrates successfully (step1715), the wall scanner 1205 is ready to detect metal objects hiddenbehind a surface (step 1720). If the wall scanner 1205 does notcalibrate correctly, a calibration error is displayed (step 1725), andthe wall scanner 1205 waits for a user to change sensing modes oractivate the calibration button 1520 again (step 1730). In someembodiments, if a user selects the stud sensing mode (step 1735), thewall scanner 1205 calibrates automatically. In other embodiments, theuser must activate the calibration button 1520. If the calibration issuccessful (step 1740), the wall scanner 1205 is ready to detect studshidden behind a surface (step 1745). If the calibration is notsuccessful, a calibration error is displayed (step 1725), and the wallscanner 1205 waits for the user to change sensing modes or activate thecalibration button 1520 again (step 1730). Following steps 1720 and1745, the wall scanner 1205 also waits for the user to change sensingmodes or recalibrate the wall scanner 1205 (step 1730). Alternatively,the user can activate the menu button 1510 from the control section 1265(step 1750) to set up wall scanner tools (step 1755) such as selectingdisplay units and turning sound on and off. To exit the tools setup, theuser activates the menu button 1510 a second time (step 1760).

Thus, the invention provides, among other things, a clamp meterconfigured to receive a removable and rechargeable battery pack. Theclamp meter includes a main body having a first axis, a handle, a clamp,a trigger, and a display. The handle has a second axis and includes afirst recess configured to receive the battery pack. The second axisforms an oblique angle with the first axis, and the battery pack isinserted into the first recess along the second axis. The clamp iscoupled to the main body, aligned with the first axis, and operable tomeasure an electrical characteristic of a conductor based on an inducedcurrent. Various features and advantages of the invention are set forthin the following claims.

What is claimed is:
 1. A test and measurement device comprising: ahousing including a recess; a sense circuit; a first battery terminaland a second battery terminal positioned substantially within therecess; a removable battery pack including a battery pack housing and acoupling mechanism that engages the housing to releasably secure thebattery pack to the housing, the battery pack housing including a firstreceptacle and a second receptacle, only a portion of the battery packhousing being insertable into the recess to engage the first batteryterminal and the second battery terminal; and a battery pack lock, thebattery pack lock having a secured state and an unsecured state,wherein, when the battery pack lock is in the secured state, the portionof the battery pack housing is prevented from being removed from therecess.
 2. The test and measurement device of claim 1, wherein thecoupling mechanism of the battery pack includes a tab, and wherein thetab engages a second recess to releasably secure the battery pack to thehousing.
 3. The test and measurement device of claim 2, wherein thecoupling mechanism of the battery pack further includes an actuator, andwherein the actuator is operable to disengage the tab from the recess.4. The test and measurement device of claim 1, wherein the battery packis a lithium-ion battery pack.
 5. The test and measurement device ofclaim 4, wherein the battery pack is a 12V battery pack.
 6. The test andmeasurement device of claim 1, wherein the battery pack housing isshaped and sized to match contours of the housing.
 7. The test andmeasurement device of claim 1, wherein the battery pack lock includes afirst end, a second end, and a central portion connecting the first endto the second end.
 8. The test and measurement device of claim 7,wherein the central portion conforms to contours of the housing.
 9. Thetest and measurement device of claim 1, wherein the battery pack lockincludes a flange for mating with the battery pack.
 10. The test andmeasurement device of claim 1, wherein the battery pack lock includes ascrew having a cam.
 11. The test and measurement device of claim 10,wherein the battery pack lock is configured to be changed from theunsecured state to the secured state by turning the screw.
 12. The testand measurement device of claim 1, wherein the sense circuit includes amicroprocessor.
 13. The test and measurement device of claim 1, whereinthe sense circuit is operable to sense a voltage.
 14. A test andmeasurement device comprising: a housing including a recess; a firstbattery terminal and a second battery terminal positioned substantiallywithin the recess; a removable battery pack including a battery packhousing and a coupling mechanism that engages the housing to releasablysecure the battery pack to the housing, a portion of the battery packhousing being insertable into the recess to engage the first batteryterminal and the second battery terminal; and a battery pack lock, thebattery pack lock having a secured state, wherein, when the battery packlock is in the secured state, the portion of the battery pack housing isprevented from being removed from the recess.
 15. The test andmeasurement device of claim 14, wherein the battery pack lock includes afirst end, a second end, and a central portion connecting the first endto the second end.
 16. The test and measurement device of claim 15,wherein the central portion conforms to contours of the housing.
 17. Thetest and measurement device of claim 14, wherein the battery pack lockincludes a flange for mating with the removable battery pack.
 18. Thetest and measurement device of claim 14, wherein the battery pack lockincludes a screw having a cam.
 19. The test and measurement device ofclaim 18, wherein the battery pack lock is configured to be changed froman unsecured state to the secured state by turning the screw.
 20. Thetest and measurement device of claim 14, further comprising a sensecircuit, wherein the sense circuit is operable to sense a voltage.